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THE CANADIAN ENTOMOLOGIST. 



The Eyes are large and prominent, one on each side of the head. 

 They may be widely separated, almost touching, barely touching at one 

 point only, or meeting for some little distance. The size of the eyefj and 

 their prominent position on the head accounts in large degree for the 

 wariness of these insects. 



The Wings are long and narrow as compared with those of butterflies. 

 In the active Dragon-flies the hind wings are quite broad at their base (next 

 the body), while in the weaker Damsel-flies they are narrowed at the base. 



In all Odonata there is a notch-like or joint-like structure on the front 

 edge of the wings about mid-way its length ; the nodus. 



The pterostigma (which is absent in some Odonata) is a distinct, 

 hardened or conspicuously coloured small patch on the front edge of the 

 wing between-the nodus and the tip of the wing, usually nearer the latter. 

 Examine a specimen carefully and you will plainly see the framework of 

 Uie wing : — hardened black lines called veins, which support the thin 

 membrane of the wing. Note that in the front part of the wing there are 

 several strong veins running lengthwise. The very front margin of the 

 wing itself is a strong vein, which extends all the way around the wing. 

 The next of these lengthwise veins usually only extends to the nodus, and 

 between it and the vein which forms the margin of the wing are a number 

 of small veins running perpendicularly between the two : — this is the 

 fi7-st series of anienodal veins, so called because they come (starting at 

 the base of the wing) before the nodus. Between this second lengthwise 

 vein which stops at the nodus and the third lengthwise vein which runs 

 light on past the nodus to the pterostigma, is the second series of antenodal 

 veins. Now, sometimes these two series of antenodal veins correspond : 

 that is, one of the second series is continuous with one of the first series, 

 as if it were one continuous antenodal vein running from the margin of 

 the wing to the third lengthwise vein. In other cases these two series of 

 antenodal veins do r.oi at all correspond, and only rarely will you find a 

 vein which is continuous from the margin to the third lengthwise vein. 



Now, ui)on the characters which we hive just discussed —(i) the 

 position and relation of the eyes ; (2) the shape of the hind wings and (3) 

 the correspondence ( m- lack of it) between the two series of antenodnl 

 veins — we may construct an easy table for separating our Odonata into 

 their six families. 



A. Eyes wide apart, projecting from the head, — the hind wings narrow 

 at basj, and the wings held vertically over the back when not in 

 use . (Damsel-flies.) 



